Spring Framework 4.x

Revolution or evolution?

Yegor Bondar

About the Presenter

Yegor Bondar

NIX Solutions Ltd.
Java Developer, Group Lead
Spring Framework fan :)

key Notes

In this talk We will try to cover:

Review new era of Spring Framework as a Platform
Provide steps to migrate your app from Spring 3.x to 4.x
Analyze and try new Spring Core and Web enhancements
Java 8 and Spring 4.x

Spring.io

Spring INITIALIZR

Spring.IO platform provides easy-to-use portal to bootstrap new application from scratch

start.spring.io

New environment - forget about legacy

Release Date: 01.10.2014
Current Release Version: 4.1.1.RELEASE
Latest Version: 4.1.2-SNAPSHOT

A new Java baseline

Java SE 6+ (minimum API level: JDK 6 u18, early 2010)

Java EE 6+ (Servlet 3.0 focused, Servlet 2.5 compatible in runtime)

All @Deprecated were removed

NEW ENVIRONMENT - FORGET ABOUT LEGACY

Common server generation

Tomcat 6.0.33+ (WebSocket support for 7.0.47 and 8.x)
Jetty 7.5+ (WebSocket support for 9.x)
JBoss 6.1+ (WebSocket support for WildFly 8.x)

Support for 3rd party libraries version 3 years back

Hibernate 3.6.9+, Ehcache 2.4.7+, Quartz 1.8.6+, Apache Tiles 2.2.2+, Hibernate Validator 4.3+

key Framework updates

New Spring sub-projects

spring-websocket & spring-messaging
spring-boot (makes it easy to create stand-alone, production-grade Spring based Applications that can you can "just run")

Java 8 support

lambdas and method references in Spring API (JdbcTemplate, MessagingTemplate)
new DateTime package support (@DateTimeFormat)
@Repeatable annotations
method parameter names handling( javac -parameters )

KEY FRAMEWORK UPDATES

Support for key JavaEE 7 technologies (like JMS 2.0, JPA 2.1, Servlet 3.1, JCache etc.)

Kill an XML: Groovy Bean Definition DSL

Core container enhancements:

generic types as qualifier
meta-annotations
@Conditional
Objenesis library is included for proxies creation
@Order annotation for bean collection injection

Spring web Updates

Spring MVC enhancements

@RestController
AsyncRestTemplate for developing non-blocking REST clients.
New static resource handling in Spring 4.1

How to Migrate Your Project?

1. Increase version of Spring dependencies

If you already have Spring 3.1.x/3.2.x then just change version to 4.x AND make sure that you added spring-context dependency:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>${spring.version}</version>
</dependency>

HOW TO MIGRATE YOUR PROJECT?

2. Update xml configuration namespaces

Make sure that you update your Spring.XSD namespaces:

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

HOW TO MIGRATE YOUR PROJECT?

3. Ensure that your 3rd party libs are compatible with Spring 4.x

E.g. Update Jackson dependencies:

 <dependency>
     <groupId>com.fasterxml.jackson.core</groupId>
     <artifactId>jackson-core</artifactId>
     <version>2.3.0</version>
 </dependency>
 <dependency>
     <groupId>com.fasterxml.jackson.core</groupId>
     <artifactId>jackson-databind</artifactId>
     <version>2.3.0</version>
 </dependency>

Spring core - new configuration

From Spring 3.x you can configure your beans and context with aim of Java (@Configuration, @Beans)

In Spring 4.x you can configure your beans and context with aim of Groovy

Spring 4.x provides new Groovy Bean DSL

Main entry point classes:

Bean definition reader: GroovyBeanDefinitionReader
Application Context: GenericGroovyApplicationContext

Groovy Bean Dsl - import

XML config:

 <import resource="classpath:/context/gbeans.groovy">

Java config:

@Configuration
@PropertySources({
    @PropertySource(value = "config.properties"),
    @PropertySource(value = "config_repeat.properties", ignoreResourceNotFound = true)
})
@ImportResource(value = "classpath:/context/gbeans.groovy")
public class ApplicationConfiguration {...}

web.xml inclusion

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:/context/gbeans.groovy</param-value>
</context-param>

Spring xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

      <bean id="gdbean" class="edu.spring.talk.gbeans.GDBean">
          <property name="name" value="testname"/>
          <property name="desc" value="testdesc"/>
     </bean>

</beans>

Groovy bean dsl

package edu.spring.talk.gbeans
import edu.spring.talk.gbeans.inner.IGADrivenBean

beans {
    gdbean GDrivenBean, name:'testname', desc:'testdesc'
    gdbeanprops(GDrivenBean){        name = 'propname'
        desc = '${test.desc}' //properties file driven
    }
    igadbean(IGADrivenBean) {bean ->
        bean.scope = 'prototype'

        reference = ref 'gdbeanprops'
        s_reference = gdbean
    }
}

Bean definition: beanName(type, constructor-args)

Advanced Groovy Bean DSL

import org.springframework.core.io.ClassPathResource

def defaultScope = 'prototype'
def properties = new Properties()
properties.load(new ClassPathResource('application.properties').inputStream);

beans {
    xmlns([ctx:'http://www.springframework.org/schema/context'])
    ctx.'component-scan'('base-package':properties.basePackage)
    igadbean(IGADrivenBean) {bean ->
        bean.scope = defaultScope
    }
}

Advanced groovy Bean dsl

You can use all common Groovy constructions

Groovy DSL has an access to the all GroovyBeanDefenition fields

beans {
    if (environment.activeProfiles.contains("dev")) {
        gdbean GDrivenBean, name:'testname', desc:'testdesc'
    } else {
        gdbean GDrivenBean, name:'prodname', desc:'proddesc'
    }
}

protected GroovyBeanDefinitionReader invokeBeanDefiningClosure(Closure callable) {
     callable.setDelegate(this);
     callable.call();
     finalizeDeferredProperties();
     return this;
}

Spring contexts - PERFORMANCE

Spring 4.x & java 8

Spring 4.x has a lot of Java 8 Lambdas-ready interfaces in Templates helpers like:

JdbcTemplate (RowMapper, PreparedStatementSetter)
JmsTemplate (MessageCreator)
TransactionTemplate (TransactionCallback)

JdbcTemplate jt = new JdbcTemplate(dataSource);
jt.query("SELECT name, age FROM person WHERE dep = ?",
    ps -> {
        ps.setString(1, "Sales");
    },
    (rs, rowNum) -> {
        return new Person(rs.getString(1), rs.getInt(2));
});

Spring 4.x & Java 8

Repeatable annotations

Before Java 8

@PropertySources({
    @PropertySource(value = "config.properties"),
    @PropertySource(value = "config_repeat.properties", ignoreResourceNotFound = true)
})public class Configuration {...}

Now w/ Java 8

@PropertySource("config.properties")
@PropertySource("config_repeat.properties", ignoreResourceNotFound = true)public class Configuration {...}

Spring 4.x & java 8

Optional Controller handler parameters

@RequestMapping(value = "/bean/{name}", method = RequestMethod.GET)
public GDrivenBean getBean(@PathVariable Optional<String> name, @RequestParam Optional<String> desc){
        bean.setName(name.orElseGet(() -> bean.getName()););
        bean.setDesc(desc.orElse("default"));
        return bean;
}

Optional Java Configuration Injections

@Bean
JDrivenBean jDrivenBean(@Qualifier("gdbean")Optional<GDrivenBean> gdbean){
        return new JDrivenBean("t");
}

Spring core - generic @Autowired

Input Case:

public class JDrivenBean<T> {
    T value;
}@Component("jstringbean")
public class JADrivenBean extends JDrivenBean<String> {...}

@Component("jlongbean")
public class JLongBean extends JDrivenBean<Long>{...}

Previous solution:

<alias name="jbean" alias="jlongbean">

@Autowired
@Qualifier("jbean")
private JLongBean bean;

Now:

@Autowired private JDrivenBean<String> genericBean;

Spring core - metannotations

With the exception of value(), meta-annotated types may redeclare attributes from the source annotation to allow user customization.

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@RequestMapping("/webservice")
@RestController
@Scope("request")
@Transactional(isolation = Isolation.DEFAULT)
public @interface WebServiceController {
    Propagation propagation() default Propagation.REQUIRES_NEW;
    String [] headers() default {};
}

@WebServiceController
public class BeanRestController {...}

Spring web Updates

@RestController - @Controller + @ResponseBody

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Controller
@ResponseBody
public @interface RestController {...}

@RestController
public class BeanController{
    @RequestMapping(value = "/get/bean", method = RequestMethod.GET)
    public TestBean get(){...}
}

Spring web - Groovy templates

yieldUnescaped '<!DOCTYPE html>'
html(lang:'en') {
  head {
   meta('http-equiv':'"Content-Type" content="text/html; charset=utf-8"')           title('My page')
  }
  body {
     p('This is an example of HTML contents') 
  }
}

The same as Freemarker and Velocity:

GroovyMarkupView/ViewResolver/Configurer

Spring web - Static resources handling (Teaser)

Major Spring Framework 4.1 feature

• Evolve existing ResourceHttpRequestHandler mechanism

• ResourceResolver and ResourceTransformer chains

• arbitrary resolution (version in URL path)

• ResourceUrlProvider

• prepare “public” resource URL (e.g. insert version)

Now you can do this:

/images/background-7fbe76cdac.png

conclusions

Spring 4.X is Production Ready - Migrate & Enjoy it!;
Groovy Bean DSL is killer of XML Configs;
You HAVE TO try new Spring projects: Spring Boot & Spring Messaging/WebSockets.

Useful resources:

Source code: https://bitbucket.org/yegorbondar/spring-4.x

Slides: https://slides.com/yegorbondar/spring-4-x

Q & a

Thank you!

spring-4.x

By Yegor Bondar

spring-4.x

ThinkJava #1 Spring 4.x talk

4,521

Spring Framework 4.x

About the Presenter

key Notes

Spring.io

Spring INITIALIZR

New environment - forget about legacy

NEW ENVIRONMENT - FORGET ABOUT LEGACY

key Framework updates

KEY FRAMEWORK UPDATES

Spring web Updates

How to Migrate Your Project?

HOW TO MIGRATE YOUR PROJECT?

HOW TO MIGRATE YOUR PROJECT?

Spring core - new configuration

Groovy Bean Dsl - import

Spring xml

Groovy bean dsl

Advanced Groovy Bean DSL

Advanced groovy Bean dsl

Spring contexts - PERFORMANCE

Spring 4.x & java 8

Spring 4.x & Java 8

Spring 4.x & java 8

Spring core - generic @Autowired

Spring core - metannotations

Spring web Updates

Spring web - Groovy templates

Spring web - Static resources handling (Teaser)

conclusions

Q & a

Thank you!

spring-4.x

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